The purpose of the proposed research is to examine the relationships of a variety of serum factors to the development of human cancer in general and at specific sites. In particular, we will test a series of hypotheses relating: (a) serum levels of antioxidant vitamins (vitamin A, carotene, and vitamin E) to cancer at all sites; (b) serum levels of selenium to cancer at all sites; (c) serum hormones (estrogens and androgens, progesterone, thyroxine, and TSH) to breast cancer in postmenopausal women; (d) serum antibodies to cytomegalovirus and serum hormones to prostatic cancer; and (e) serum antibodies to Epstein-Barr virus to Hodgkin's disease. To accomplish these objectives, we will utilize sera that were collected and stored at -70 C in 1973 and again in 1978 from approximately 10,000 persons who participated in the Hypertension Detection and Follow-Up Program (HDFP). These participants already have been followed through 1981. We propose to continue to follow participants at 11 of 14 HDFP clinical centers for another five years, using mailed questionnaires and telephone interviews. Incident cancer cases will be identified and documented with hospital records and/or death certificates. Over the total of 12 years of follow-up encompassed by this study, we estimate that we will be able to analyze the prediagnostic serum from 530 individuals with incident cancers, including 59 cases of breast cancer and 42 cases of prostatic cancer. Relevant serum analyses will be performed for these cases and series of matched controls from the HDFP cohort. Matched analyses will be used to evaluate the relationships between exposures of interest and risk of subsequent cancer. Information from the HDFP data base will be used to control for potential confounding variables. The long-term objective of this research is to determine the role of certain vitamins, trace metals, hormones, and herpesviruses in the pathogenesis of human cancer.